Photographic objective.



uransman.

UNITED STATES PATENT OFFICE.

PAUL RUDOLPH, OF JENA, GERMANY, ASSIGNOR TO THE FIRM OF CARL ZEISS, OF JENA,

GERMANY.

PHOTOGBAPHIC OBJECTIVE.

Specification of Letters Patent.

Patented May 5, 1908.

To all whom it may concern:

Be it known that I, PAUL RUDOLPH, doc tor of philosophy, a citizen of the German Empire, and residin at Carl Zeiss strasse, Jena, in the Grand uchy of Saxe-Weimar, Germany, have invented a new and useful Photographic Objective, of which the following is a specification. I

The invention relates to tri le-lensphotoaphic objectives with a diap agm in front, 1n which a collective cemented front surface presents the convexity and a dispersive cemented back surface the concavity towards the diaphragm. Such objectives are already shown in the patent specification 528155, Figure 2, and they are shown and described in the British patent specification 4692 93, Fig. 1. While, however, in the objective described in 4692/93 with reference to Fig. 1 the kinds of lass are chosen, so that the difference in ind amount as at the collective cemented surface, according to the present invention a more perfect correction of the spherical or the astigmatic aberration can be obtained by 1 persive one. The result of this improvement may be directed to manifest itself either in a spherical correction for a relatively large a erture, or in diminished zones of spherical aberration, or in diminished astigmatlc difierences combined with satisfactory flatness of the image. This result extends not only to single objectives, in which the sine condition is fulfilled simultaneously with spherical correction, but also to systems, in which little or no regard has been paid to the sine condition. In the first case good components for convertible objectives can be obtained, in the second, components, of which two must be combined into a double objective in order to show a quite satisfactory correction.

In the annexed drawing: Fig. 1 represents a single objective constructed accordin to the invention and corrected so as to fuIfil also the sine condition. 2 represents a double objective constructed according to the invention, neither component obex of refraction at the dispersive cemented surface is about the same jective being corrected as to the sine condi- Radii, Thicknesses and Distances.

1' =15. 0 b =1. 4 r,=36.4 a, =0.s 7' 6.9 d11=2.0 r,=15. 6 d =2.2 Kinds ofGZass. I:n =1. 4967 fil /=1. 5063 II I 71/1 n =1.6286 II1:'IL =1. 6570 n =1. 6810 Example 2 (Fig. 2). Spherically, asti matically and chromatically corrected doub e objective of two equal triple lenses, in either of which a collective lens II is inclosed between two dispersive lenses I and III. The two components are symmetrically arranged in front of and behind the dia hragm D. The relative aperture of the doub e ob ective is 1 6.3.

Radial, Thicknesses and Distances.

r,=20. 3 6 =2. 7 r,=54.8 a =1.0 1' =10.7 (i =4.1 7' d111=2. 1

Kinds of Glass. I :n =1.4626 n =1.4714 II n 1. 5832 n 1. 5972 III n 1. 6240 n 1. 6448 I claim:

1. In a hotographic objective the combination of three cemented lenses having a collective gemfintgd silgface neaar todand convex towar s t e ia a an a is ersive cemented surfaoTliEtafitIIiom and ciincave towards the diaphragm, the difference between the refractive indices at the collective cemented surface amounting to at least nent the difference between the refractive in- 10 double the difference at the dispersive cedices at the collective cemented surface mented surface. amounting to at least double the difierence W h2. hDouble ob%ecfi1i ve, each colnliponent 0g at the dispersive cemented surface. 5 w ic consists 0 t ee cemente enses Wit a collective cemented surface near to and PAUL RUDOLPH f convex towards the diaphragm and a dispers- Witnesses: v 51 ive cemented surface distant from and con- PAUL KRI'iGER, cave towards the diaphragm, in each compo- FRITZ SANDER. 

